The Obama administration is expressing confidence in the formation of an international coalition to combat Islamic State radicals who control swaths of territory in Iraq and Syria. But congressional action in support of the effort is a matter of growing debate.

After meeting with allies and partners in the Middle East, Secretary of State John Kerry says a growing list of nations is prepared to strike against Sunni militants, a point echoed by White House Chief of Staff Denis McDonough, who uses the ISIL acronym for the group.

“What we want to make sure happens is that we have committed partners who can take the fight to ISIL on the ground. And they will have not only support from us form the air, but training and equipment,” said McDonough, speaking on ABC’s This Week program.

That coalition will be essential if Islamic State militants are to be defeated without the deployment of U.S. ground forces in a combat role. Another encouraging sign is the formation of broad-based Iraqi government, according to McDonough.

“There is now a new, multi-ethnic government in Baghdad. They will support a unified, capable, multi-ethnic Iraqi force, so that they can take this fight to ISIL,” said McDonough.

A supporting U.S. role has the backing of independent Senator Angus King.

“This cannot be a war of Westerners against Islam. This has to be an area of the world that is willing to police itself,” said King.

But with lawmakers eager to adjourn well in advance of the November midterm elections, it is not clear whether or when votes will be held to authorize any portion of the strategy President Barack Obama outlined last week.

Republican Senator Susan Collins believes the U.S. commander-in-chief should have acted sooner.

“The president waited far too long to present a strategy to the American people and to Congress. Now we are being asked to react on a very short timeline, in a matter of days,” said Collins.

President Obama is not asking formal congressional authorization to strike against the Islamic State. That is a mistake, according to Republican Senator Bob Corker, who nonetheless backs military action.

“Problems occur. And I think the administration would be so much wiser to get that authorization from Congress on the front end, instead of having over time 535 Monday morning quarterbacks (second-guessers in Congress),” said Corker, referring to the number of lawmakers in the U.S. legislature.

Meanwhile, the Islamic State’s latest atrocity, the beheading of British aid worker David Haines, is provoking strong reactions on both sides of the Atlantic. The White House condemned the killing as barbaric, while British Prime Minister David Cameron said IS militants are “the embodiment of evil.”